The Inertio-Elastic Planar Entry Flow of Low-Viscosity Elastic Fluids in Micro-fabricated Geometries

The non-Newtonian flow of dilute aqueous polyethylene oxide (PEO) solutions through microfabricated planar abrupt contraction-expansions is investigated. The contraction geometries are fabricated from a high-resolution chrome mask and cross-linked PDMS gels using the tools of soft-lithography. The small length scales and high deformation rates in the contraction throat lead to significant extensional flow effects even with dilute polymer solutions having time constants on the order of milliseconds. The dimensionless extra pressure drop across the contraction increases by more than 200% and is accompanied by significant upstream vortex growth. Streak photography and videomicroscopy using epifluorescent particles shows that the flow ultimately becomes unstable and three-dimensional. The moderate Reynolds numbers (0.03 ≤ Re ≤ 44) associated with these high Deborah number (0 ≤ De ≤ 600) microfluidic flows results in the exploration of new regions of the Re-De parameter space in which the effects of both elasticity and inertia can be observed. Understanding such interactions will be increasingly important in microfluidic applications involving complex fluids and can best be interpreted in terms of the elasticity number, El = De/Re, which is independent of the flow kinematics and depends only on the fluid rheology and the characteristic size of the device.

Un assaig del premi Espais [Ressenya del llibre El cant de les sirenes. Ressons postmoderns en la fotografia contemporània espanyola, de Jordi Alberich i Pascual]

Ressenya del llibre El cant de les sirenes. Ressons postmoderns en la fotografia contemporània espanyola. Aquest assaig està dedicat a l’evolució recent de la fotografia espanyola on es prova d’esbrinar el paper que la teoria postmoderna ha pogut tenir en el trànsit de la fotografia al llarg del període tractat

Morguefile website

A morgue file is a place to keep post production materials for use of reference, an inactive job file. This morgue file contains free high resolution digital stock photography for either corporate or public use. The term "morgue file" is popular in the newspaper business to describe the file that holds past issues flats. Although the term has been used by illustrators, comic book artist, designers and teachers as well. The purpose of this site is to provide free image reference material for use in all creative pursuits. This is the world wide web's morguefile.

Introduction to Lenses

As part of the workshop in lenses to graphic arts-photography

Fundación Manuel H.

El proyecto “A través del lente de Manuel H.” plantea diseñar una Fundación cuya misión es fortalecer y reconstruir la memoria de Bogotá a partir de los relatos históricos expresados en las imágenes capturadas por el Maestro Manuel H entre 1946 y 2009. Se trabajará dicho fortalecimiento a partir de tres líneas de productos que se desarrollarán durante los seis primeros a��os de existencia de la Fundación. Las líneas de servicios que se plantean desarrollar inicialmente, hacen referencia a exposiciones innovadoras utilizando los nuevos conceptos de las artes visuales, actividades académicas y proyectos de responsabilidad social enfocados a la fotografía, las temáticas de la colección y al Maestro Manuel H.

Structural Chromosomal Alterations Induced by Dietary Bioflavonoids in Fanconi Anemia Lymphocytes

Introduction Fanconi anemia is an autosomal recessive disease characterized by a variety of congenital abnormalities, progressive bone marrow failure, increased chromosomal instability and higher risk to acute myeloid leukemia, solid tumors. This entity can be considered an appropriate biological model to analyze natural substances with possible genotoxic effect. The aims of this study were to describe and quantify structural chromosomal aberrations induced by 5 flavones, 2 isoflavones and a topoisomerase II chemotherapeutic inhibitor in Fanconi anemia lymphocytes in order to determine chromosomal numbers changes and/ or type of chromosomal damage. Materials and methods Chromosomes stimulated by phytohaemagglutinin M, from Fanconi anemia lymphocytes, were analysed by conventional cytogenetic culture. For each chemical substance and controls, one hundred metaphases were evaluated. Chromosomal alterations were documented by photography and imaging analyzer. To statistical analysis was used chi square test to identify significant differences between frequencies of chromosomal damage of basal and exposed cell cultured a P value less than 0.05. Results There were 431 chromosomal alterations in 1000 metaphases analysed; genistein was the more genotoxic bioflavonoid, followed in descendent order by genistin, fisetin, kaempferol, quercetin, baicalein and miricetin. Chromosomal aberrations observed were: chromatid breaks, chromosomal breaks, cromatid and chromosomal gaps, quadriratials exchanges, dicentrics chromosome and complex rearrangements. Conclusion Bioflavonoids as genistein, genistin and fisetin, which are commonly present in the human diet, showed statistical significance in the number of chromosomal aberrations in Fanconi anemia lymphocytes, regarding the basal damage.

Especímenes antropométricos y curiosidades pintorescas: la orquestación fotográfica del cuerpo “negro” (Brasil circa 1865)

Paul Gilroy escribe en Against Race que la “producción de la raza��� desencadenada en los siglos XVIII y XIX “necesitó una síntesis de logos e ícono, de la racionalidad científica formal acompa��ada de algo más, algo visual y estético” (1). A partir del siglo XIX y de la mano de los avances tecnológicos en el ámbito de la representación visual, especialmente en la fotografía, los discursos científicos de la alteridad acogen y desarrollan un componente de exhibicionismo y espectacularización.En este marco de ideas, se pretende entender la producción fotográfica del cuerpo “negro”, en específico algunas imágenes que conforman los archivos fotográficos creados por el científico Louis Agassiz y Christiano Júnior en Brasil a mediados del siglo XIX. Objetivo: indagar la manera en que estos procedimientos de visualización contribuyeron a re-ensamblar discursos raciales en Brasil y en Estados Unidos justo en el momento cuando el cuerpo “negro” se enviste de subjetividad legal.